CARD15/NOD2 functions as an antibacterial factor in human intestinal epithelial cells

Tadakazu Hisamatsu, Manabu Suzuki, Hans Christian Reinecker, William J. Nadeau, Beth A. McCormick, Daniel K. Podolsky

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524 Citations (Scopus)

Abstract

Background & Aims: Mutations in the CARD15/NOD2 gene, a putative intracellular pattern recognition receptor, have been linked to the risk for Crohn's disease. Because intestinal epithelial cells play a role as the barrier to luminal microorganisms, we investigated the expression and function of CARD15/NOD2 in intestinal epithelial cells. Methods: Expression of CARD15/NOD2 messenger RNA (mRNA) in intestinal epithelial cell lines and primary intestinal epithelial cells was assessed by reverse-transcription polymerase chain reaction (RT-PCR). Regulation of expression of CARD15/NOD2 by cytokines was determined by Northern blot using the SW480 cell line. Active CARD15/ NOD2 protein in SW480 cells was assessed by the combination of immunoprecipitation and immunoblotting using anti-CARD15/NOD2 antisera. To identify the functional role of CARD15/NOD2 in intestinal epithelial cells, gentamicin protection assays of Salmonella typhimurium were performed using Caco2 cells stably transfected with either wild-type CARD15/NOD2 or the 3020insC mutant associated with Crohn's disease. Results: CARD15/NOD2 mRNA was expressed in both intestinal epithelial cell lines and primary intestinal epithelial cells. CARD15/NOD2 mRNA and protein were up-regulated by tumor necrosis factor α (TNFα) in SW480 cells. The number of viable internalized S. typhimurium in Caco2 cells stably transfected with CARD15/NOD2 expression plasmid was lower than untransfected Caco2 cells or MOCK transfectant. In contrast, expression of a variant associated with Crohn's disease was unable to constrain bacterial survival. Conclusions: CARD15/NOD2 is expressed in intestinal epithelial cells and may serve as a key component of innate mucosal responses to luminal bacteria as an antibacterial factor. Failure in this activity may contribute to the development of Crohn's disease.

Original languageEnglish
Pages (from-to)993-1000
Number of pages8
JournalGastroenterology
Volume124
Issue number4
DOIs
Publication statusPublished - 2003 Apr 1

ASJC Scopus subject areas

  • Hepatology
  • Gastroenterology

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    Hisamatsu, T., Suzuki, M., Reinecker, H. C., Nadeau, W. J., McCormick, B. A., & Podolsky, D. K. (2003). CARD15/NOD2 functions as an antibacterial factor in human intestinal epithelial cells. Gastroenterology, 124(4), 993-1000. https://doi.org/10.1053/gast.2003.50153